Editing Mendelevium (section)

===Atomic===
A mendelevium atom has 101 electrons. They are expected to be arranged in the configuration [Rn]5f<sup>13</sup>7s<sup>2</sup> (ground state [[term symbol]] <sup>2</sup>F<sub>7/2</sub>), although experimental verification of this electron configuration had not yet been made as of 2006. The fifteen electrons in the 5f and 7s subshells are [[valence electron]]s.<ref name="Silva16334">Silva, pp. 1633–4</ref> In forming compounds, three valence electrons may be lost, leaving behind a [Rn]5f<sup>12</sup> core: this conforms to the trend set by the other actinides with their [Rn]&nbsp;5f<sup>''n''</sup> electron configurations in the tripositive state. The first [[ionization potential]] of mendelevium was measured to be at most (6.58&nbsp;±&nbsp;0.07)&nbsp;[[electronvolt|eV]] in 1974, based on the assumption that the 7s electrons would ionize before the 5f ones;<ref name="NIST">{{cite journal|first1=W. C. |last1=Martin |first2=Lucy |last2=Hagan |first3=Joseph |last3=Reader |first4=Jack |last4=Sugan |date=1974 |title=Ground Levels and Ionization Potentials for Lanthanide and Actinide Atoms and Ions |url=https://www.nist.gov/data/PDFfiles/jpcrd54.pdf |journal=J. Phys. Chem. Ref. Data |volume=3 |issue=3 |pages=771–9 |access-date=2013-10-19 |doi=10.1063/1.3253147 |url-status=dead |archive-url=https://web.archive.org/web/20140211144635/https://www.nist.gov/data/PDFfiles/jpcrd54.pdf |archive-date=2014-02-11 |bibcode=1974JPCRD...3..771M }}</ref> this value has since not yet been refined further due to mendelevium's scarcity and high radioactivity.<ref>David R. Lide (ed), ''CRC Handbook of Chemistry and Physics, 84th Edition''. CRC Press. Boca Raton, Florida, 2003; Section 10, Atomic, Molecular, and Optical Physics; Ionization Potentials of Atoms and Atomic Ions</ref> The ionic radius of [[coordination number|hexacoordinate]] Md<sup>3+</sup> had been preliminarily estimated in 1978 to be around 91.2&nbsp;pm;<ref name="Silva16356" /> 1988 calculations based on the logarithmic trend between [[distribution coefficient]]s and ionic radius produced a value of 89.6&nbsp;pm, as well as an [[enthalpy of hydration]] of {{val|−3654|12|u=kJ/mol}}.<ref name="Silva16356" /> Md<sup>2+</sup> should have an ionic radius of 115&nbsp;pm and hydration enthalpy −1413&nbsp;kJ/mol; Md<sup>+</sup> should have ionic radius 117&nbsp;pm.<ref name="Silva16356" />